Railway-signal.



H. DIBHL.

RAILWAY SIGNAL.

APPLIGATION FILED APR.23,1907.

901,958. Patented Oct. 27, 1908.

Figi I WPCHGSSQS llrwe njfor.

l Henr h Diehl.

UNITED STATES PATENT orrlcu.

HEINRICH DIEHL, OF BERLIN, GERMANY, ASSIGNOR TO GENERAL ELECTRICCOMPANY,

. A CORPORATION OF NEW YORK.

RAILWAY-SIGNAL.

Speccation of Letters Patent.

Patented oct. 27, 190s.

Application mea April 2s, 1907. serial No. 369,856.

systems in which the control. of the signals is secured by the coperation of selenium cells placed along the trackway and sources of light on the cars. The resistance of a selight falling on the cell from other sources than that on a passing car.. For instance, the lvariation in sunlight through the day may exercise a disturbing inliuence on the cell and the devices in circuit with it.v

My present invention has for its object to eliminate such disturbances. For this purpose I take advantage of the fact that while the variations in the light thrown on the cell 'by a passing car are sudden, the variations d ue to other causes, such as sunlight, are gradual.

My invention consists in so arranging the signal-controlling devices that they respond only t0 a sudden variation of current in the cell circuit. This result may be secured by controlling the signal -by a current produced illductively by the current in the circllit of the selenium cell, as by using a relay of the induction type, or by inserting a transformer between the cell and the relay.

My invention will best be understood by reference tothe accompanying drawings, in which Figure l shows diagrammatically a car provided with a source of light and a Sele-- nium cell arrangedto be affected thereby; and Fig. 2 is a diagram ofthe circuit connections of a signal system arranged in accordance with my invention.

In the drawings A represents a car carrying a source of light B. This source may be of any suitable character.

C represents a selenium cell placed adjacent to the track and provided with a hood arranged to receive the rays of light from the source B. A battery D and the pri'- mary of a transformer E are connected in series with the cell C'. To the secondary of the transformer is connected a relay F. With this arrangement the relay is not affected by any adual change of current in the circuit of t le cell, such as would be pro-A duced by a variation in sunlight, but responds only to a sudden variation of current in the cell circuit, such as would be i produced by the light thrown on the cell by a passing train. The relay F controls a relay Gr,4 the armature of which is in circuit with the operating mechanism H of a signal I.'

.J represents a battery or other suitable source for the operating mechanism.

The signals are shown as operating on a normal clear principle, but it will be understood that they might. equally well be operated on the normal danger plan.

In the operation of the system as arranged in Fig. 2, the car A, moving in the direction of the arrow, throws light from the source. B onto the cell C in passing it,

thereby producing a sudden fluctuation in the resistance of the cell. This produces a sudden variation vof current-flow in the circuit of the cell, which induces a current in the secondary of transformer E. Relay F is vmomentarily energized by this current,

.to danger. Although relay F is energized only momentarily, `and drops its armature again as soon as the car has passed the cell C, relay G does not pick, u its. armature, Y l

since its own circuit, as wel as the circuit of the operating mechanism, has been broken. Signal I consequently remainsl at danger untll the car reachesthe cell C. When relay F is energized, Vthereby setting signal Iat danger, as has been above eX- plained, its lower armature closes a shunt arma-ture of relay G, when raised, not only closes the circuit of the operating mechanism of` signal I, but also maintains the relay winding G energized.

rIhe specic connections of the signalcontrolling devices described above form no part of my present invention, and I do not desire to limit myself to the particular construction and arrangement of parts here shown, but aim in the appended claims to cover all modications which are within the scope of my invention.

What I claim as new and desire to secure by Letters Patent ofthe United States, is,

l. In a railway signal system, a device adjacent to the traclcway that varies in resistance with variation in light, means carried by a moving car for varying the light on said device, a source of current in circuit with said device, and signal controllingy means responsive only to a sudden variation in the current from said source. v

2. In a railway signal system, a selenium cell adjacent to the trackway, means carried by a moving car for throwing light on said cell.a source of current in circuit with-said cell, and signal controlling means responsive only toV a sudden variation inV the current from said source.

Y 3. In a railway signal system, a device adjacent to the trackway that varies in resistance with variation in light, means carriedby a moving car for varying the light on said device, a source of current in circuit with said device, an inductive winding in etienne jacent to the trackway that varies in resist ance with variation in light, means carried by a moving car for varying the light on said device a source of current in circuit with said device, a transformer having its primary in circuit with said cell and said source, vand signal-controlling means conA nected to the secondary of said transformer.,

6. In a railway signal system, a selenium cell adjacent to the trackway, means carried by a moving car for throwing light on said cell, a source of current in circuit with said cell, a transformer having its primary in circuit with said cell and 'said source, and sig nal-controlling means connected vto the secondary of said transformer.

In witness whereof, I have hereunto set my hand this tenth day ot' April, 1907.

HEINRICH DIEHL.

Witnesses:

JULIUS RUMLAND, OSKAR SINGER. 

